İÇME SUYUNDA AGRESİVİTENİN SAPTANMASI VE ŞEBEKEDE KOROZYONUN ÖNLENMESİ

Corrosion is a complex series reactions between the water and metal surfaces and materials in which the water is stored or transported. The corrosion processes is an oxidation/reduction reaction that returns refined or processed metal to their more stable ore state. With respect to the corrosion potential of Tahtalı Dam drinking water, the primary concerns include the potential presence of toxic metals, such as lead and copper, detoration and damage to household plumbing, and aesthetic problems such as; stained laundry, bitter taste and reddish-brown stains around basins and drains. This project describes the process of determining the water quality, water quality index (WQI) for Tahtalı Dam waters as well as the results of application of the index for water evaluation in İzmir, for a one year period. The WQI includes the parameters of temperature, anions and cations and heavy metals, iron bacteria, all the physical, chemical and some bacteriological parameters, mineralization, corrosion coefficient, dissolved gases, etc. Relation between corrosive surface water, water chemistry and distribution system (pipeline network) in İzmir were evaluated by use of series monitoring and several corrosion indexes. Water-chemistry information for water samples collected each month from Görece Water Treatment Plant’s influent-effluent waters and from the city houses from 1999 to 2001 was used to determine its quality and also to calculate corrosion index. Water is considered corrosive if the index value is negative, preventing the precipitation of calcium carbonate, therefore, allowing corrosive reactions with the interior of piping system. Microbialy related water quality problems are of particular interest because ferrous materials have been found to support larger populations of attached microorganisms even in the presence of disinfectants. These types of waters which generally contain high ionic concentration and dissolved carbon dioxide will increase the conductivity of water promoting corrosion. Corrosion can also be accelerated by low pH, low flow rate within the piping, high water temperature and presence of suspended solid and excess chlorine. Over the next few years, all regulated community water systems will be required to monitor their levels of lead and copper, with samples being taken from cold water taps in consumer’s homes.